Question

Make a drawing of a metal rod that has length 12cm and a total mass of 70g including two metal loops at both ends, which go around two metal poles. The rod is in good electrical contact with the poles but can slide freely up and down. The metal poles are connected by wires to a battery, and a 5A current flows through the rod. A magnet supplies a large uniform magnetic field B in the region of the rod, large enough that you can neglect the magnetic fields due to the 5A current. The magnetic field is oriented so as to have the maximum effect on the rod. The rod sits at rest 4cm above the table. What is the magnitude of the magnetic field in the region of the rod?